Paper end indicator for typewriters



May 28, 1963 W. J. ASHWORTH PAPER END INDICATOR FOR TYPEWRITERS Filed Nov. 16, 1961 INVENTOR: WILLIAM J. ASHWORTH ATT'YS ite 3,091,321 Patented May 28, 1963 ice 3 091 321 PAPER END INDICATQR Fon rrrnwnrrnns William J. Ashworth, New Albany, Miss, assignor to Artnell Company, Chicago, 111., a corporation of Delaware Filed Nov. 16, 1961, Ser. No. 152,777 2 Claims. (Cl. 197-189) My invention relates to a new and useful improvement in a paper end indicator for typewriters and more particularly to an apparatus which may be incorporated into a typewriter or associated with an electrical typewriter which will function to indicate to the operator the position of the bottom edge of the typewriter paper sheet relative to the line of typing.

A principal object of my invention is in the provision in an electrical typewriter of an electrically operated automatic paper end indicator.

Another principal object of my invention is in the provision in an apparatus of this character of a means for visually indicating to a typist the position of the end of the typewriter paper sheet relative to the line of typing appearing before the typist.

A further object of my invention is in the provision in an apparatus of this character of a means for first indicating that a predetermined amount of paper remains in the typewriter thus permitting an operator to determine a proper typing pattern, and a second indicator for signalling the exhausting of paper in the typewriter, the indicators being connected together in an electrical circuit which is adapted to independently and successfully energize the indicators.

Yet another object of my invention is in the provision in an electrical typewriter of a plurality of independent operatively related visual indicators consisting of different colored lamps electrically energized through the absence of a paper sheet which functions as an electrical insulator between current conductors comprising the typewriter platen and certain of the paper feed rollers.

Other objects will appear hereinafter.

The invention consists in the novel combination and arrangement of parts to be hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawings showing the preferred form of construction, and in which:

FIG. 1 is a part perspective view of the typewriter platen and paper feed rollers including a schematic electrical circuit.

FIG. 2 is a schematic electrical circuit as contained in my invention, and

FIG. 3 is a side elevational sectional detailed view of one form of an electrical conductor for the typewriter platen.

The invention disclosed hereinafter has for its primary object the provision of a plurality of successfully energized indicators for enabling a typewriter operator to determine exactly when to take a sheet of typewritten paper from the typewriter, and to enable the typist to make exact margins at the lower edge of the typewritten page, the indicators being automatically energized so as to permit the aforest-ated objects to be accomplished.

Referring to FIG. 1, there is shown a typewriter platen 1i) rotatably mounted upon a supporting shaft 11. The standard typewriter structure provides a second shaft 12 extending parallel to and in spaced relation to the platen shaft 11. Rotatably mounted upon the shaft 12 are a plurality of paper feed rollers 13. Normally, these rollers are for-med of a rubberized material and in the embodiment of my invention shown, such rollers are to be employed with the exception of the indicator roller 13 which will be formed of any suitable electrically conductive material. A third shaft 14 supports a plurality of paper feed rollers 15 tangently positioned with respect to the rollers 13 and platen 10. Of these paper feed rollers 15, roller 16 is to be formed of an electrically conductive material. The shafts 12 and 14 are suitably insulated from the typewriter chassis by non-conductive bushings 12 and 14' in which the shafts are journaled.

In reference to FIG. 2 wherein I disclose the preferred electrical circuit to be incorporated in this invention, there is shown a Volt A.C. power bus including lines 17 and 18. In line 17 is positioned a manually operated off-on switch 19. The electrical typewriter motor 20 is connected directly to power lines 17 and 18 and energized through the closing of the switch 19'.

An electrical conductor 21 extends from line 17 between the switch 19 and one side of the motor 20. The conductor 21 is provided with a 2000 ohms resistor 22 and is grounded as at 23- to the chassis of the typewriter (not shown). A conductor 24 is then electrically connected between the chassis of the typewriter and the shaft 11 of the platen 10, or if desired, the chassis itself may funtion as the conductor 24. The electrical conductor paper feed roller 13' is by a conductor 26 and a common line 27 connected to the power line 18-. This conductor 26 contains a first indicator means 28. A 1500 ohms resistor 28' is interposed in the conductor 26 between the roller 13 and the first indicator 28'. Connected in parallel circuit to the first indicator 28 is a second indicator 29. This second indicator 29 is electrically connected to a conductor 30' which has one end electrically connected to the electrically conductive paper feed roller 16 and its opposite end connected to the common line 27 as seen in FIG. 2.

Referring to FIG. 1, I show that the typewriter platen 10 is provided with an electrical conductive band 31 which extends about the periphery of the platen 10 and which is in rolling engagement with the electrical conductive paper feed rollers 13 and 16. This electrical conductive band 31 is in turn connected to the shaft 11 which in turn is connected to the conductor 24.

In FIG. 3 I disclose a form of electrical connection be tween a conductive band on the platen 10 and the platen shaft 11.

In this form a. copper wire or band 32 is tightly wound around the periphery of the platen 10 adjacent one end thereof and secured to a stud 33 which in turn is screwed into the platen shaft 11. The shaft 11 is in turn then connected to the conductor 24 grounded to the chassis as at 25 as shown in FIG. 2.

From the foregoing description of parts, it is evident that when the off-on switch 19 is manually actuated into a closed or on position, the typewriter motor 20 is energized as well as the electrical circuits to the indicator. However, due to the arrangement of parts in the indicator circuits, only the second indicator 29 will be energized. This by reason hereinafter made apparent.

This circuit to the second indicator 29 can be extinguished by a sheet of paper which is inserted into the machine and caused to pass between the platen 1i) and the paper feed rollers 13" and 16. The paper sheet is non-conductive and will disrupt the circuit to the indicators, extinguishing the same. As the paper is caused to advance so that the bottom edge thereof clears or passes beyond the rolling engagement between the electrical conductive paper feed roller 13' and the electrical conductive band 31 on the platen 10, an electrical current will flow through the resistor 22, through the typewriter chassis, through the platen shaft 11 to the conductive band 31 carried by the platen 10 through the roller 13', through the resistor 28, through the first indicator 28, conduit 26,

and common line 27, completing a circuit to the power source and causing the indicator 28 to be energized. In the circuitry shown herein the indicators are small incandescent lamps of different colors. The energization of the first indicator 28 informs the operator or typist that a predetermined amount of paper is in the typewriter and available for use.

When the paper advances to the point where it will clear or pass beyond the rolling engagement between the electrical conductive paper feed roller 16 and the electrical conductive band 31 carried by the platen 10, the second indicator 29 is connected in parallel circuit with the first indicator 28. By the specific circuitry and components therein which are hereinafter described, the first indicator 28 will become extinguished and the second indicator 29 will be illuminated. The energization of the second indicator 29 informs the operator that the bottom edge of the paper sheet has been reached and that no additional print should be applied to the paper.

For the specific operation of my invention the first indicator or lamp 28 should require 28 volts at .035 amps. to be illuminated. The first indicator or lamp 28 will also have a resistance value of 280 ohms.

This second indicator or lamp 29 should require 2 volts at .06 amp. to become illuminated. As such, the second indicator or lamp 29 will have a resistance value of 30 ohms. The difference in resistance created through the parallel circuits containing the first and second indicators results in successive illumination thereof.

It is apparent from the foregoing description of the components of each of the parallel circuits that the circuit of the first indicator 28 has a total resistance of 1780 ohms; i.e. 1500 ohms for resistor 28 and 280 ohms resistance in lamp 28. Thus when the parallel circuit of the second indicator 29 is energized, the effective resistance of the circuit drops to approximately 30 ohms which is the resistance of the second indicator 29'. This 30 ohms resistance is in series with the 2000 ohm resistor 22 and this results in a voltage drop across the parallel circuit of approximately 2 volts at .06 amp. This is sufficient voltage to cause the second indicator 29 to be illuminated but insuflicient to maintain the first indicator 28 illuminated.

From the foregoing, it is apparent that I have devised an automatic electrical visual indicating system' for signalling to the operator of the typewriter the exact location of the bottom edge of the paper sheet.

It should be noted that the electrical conductive band 31 on the platen may be formed of a current conductive rubberized material so that the platen 10 may have an uninterrupted circular surface throughout its length. It may be noted that also in place of the lamps shown in this circuit as the first indicator 28 and second indicator 29 an impulse indicator such as a bell, or the like, may be used.

In adapting the principle of my invention to a nonelectrical typewriter, the identical circuit may be used omitting therefrom the typewriter motor 20. When the above described circuitry and electrical components thereof are to be employed in a manually operable typewriter the paper release lever, which is a standard component of the typewriter apparatus may be manually actuated to physically separate the rear paper feed rollers 13 and front paper feed rollers 15 from contact with the typewriter platen 10, thus disturbing the electrical circuit therebetween.

While I have illustrated and described the preferred form of construction for carrying my invention into effect,

this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do

. not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

l. A paper end position indicator means for typewriters having a rotatable platen' and front and rear paper-feed rollers normally urged toward contact with the platen, said means comprising (a) an electrical circuit having a source of electrical energy,

([2) an electrically conductive circumferential surface on said platen and means connecting said surface to one side of said electrical circuit (1) said front and rear feed rollers being electrically conductive and engageable with the conductive surface of the platen and being connected by parallel respective leads to the other side of said electrical circuit (2) said feed rollers each completing said electrical circuit through said platen and its respective lead except when separated from contact with the platen by an interposed sheet of paper,

(0) a signal light connected serially in each feed roller lead and energized independently upon contact of the respective feed roller with said platen upon passage of the end of said paper sheet beyond said respective feed roller, and

(d) means in the rear feed roller lead electrically res-ponsive to the energization of the signal light in the front feed roller lead for extinguishing the signal light in the rear feed roller lead when the electrical circuit through both said leads is completed.

2. A paper end position indicating means for an electric typewriter having a rotatable platen and front and rear paper feed rollers normally urged toward rolling contact with the platen, said means comprising i (a) an electric circuit for said typewriter including an electric motor, a source of electrical energy, and a manually operated switch for controlling said electric circuit,

(b) an electrically conductive circumferential area on the surface of said platen and means connecting said conductive area to one side of said electric circuit in parallel with said motor and on the motor side of said switch,

(1) said feed rollers being electrically conductive and engageable with the conductive area of said platen,

(c) first and second leads respectively connecting the rear and front feed rollers in parallel to the other I side of said electric circuit,

('1) each of said lea ds completing the said electric circuit through the platen and the respective feed roller except when the feed roller is separated from contact with the platen by an interposed sheet of paper,

(d) a signal light connected serially in each of said leads for energization upon contact of the respective feed roller with said platen to indicate the passage of the end of a paper sheet from between the respective feed roller and the platen, and

(e) means in the circuit of said first lead responsive to energization of the signal light in the second lead for extinguishing the signal light in the first lead when the light in the second lead is energized.

References Cited in the file of this patent UNITED STATES PATENTS 1,071,780 Neidig et al. Sept. 2, 1913 1,114,633 Neidig Oct. 20, 1914 1,132,008 Hawkins Mar. 16, 19 15 2,474,951 McCoy July 5, 1949 2,913,096 Boling Nov. 17, 1959 

1. A PAPER END POSITION INDICATOR MEANS FOR TYPEWRITER HAVING A ROTATABLE PLATEN AND FRONT AND REAR PAPER-FEED ROLLERS NORMALLY URGED TOWARD CONTACT WITH THE PLATEN, SAID MEANS COMPRISING (A) AN ELECTRICAL CIRCUIT HAVING A SOURCE OF ELECTRICAL ENERGY, (B) AN ELECTRICALLY CONDUCTIVE CIRCUMFERENTIAL SURFACE ON SAID PLATEN AND MEANS CONNECTING SAID SURFACE TO ONE SIDE OF SAID ELECTRICAL CIRCUIT (1) SAID FRONT AND REAR FEED ROLLERS BEING ELECTRICALLY CONDUCTIVE AND ENGAGEABLE WITH THE CONDUCTIVE SURFACE OF THE PLATEN AND BEING CONNECTED BY PARALLEL RESPECTIVE LEADS TO THE OTHER SIDE OF SAID ELECTRICAL CIRCUIT (2) SAID FEED ROLLERS EACH COMPLETING SAID ELECTRICAL CIRCUIT ROLLERS EACH COMPLETING SAID ELECTIVE LEAD EXCEPT WHEN SEPARATED FROM CONTACT WITH THE PLATEN BY AN INTERPOSED SHEET OF PAPER, (C) A SIGNAL LIGHT CONNECTED SERIALLY IN EACH FEED ROLLER LEAD AND ENERGIZED INDEPENDENTLY UPON CONTACT OF THE RESPECTIVE FEED ROLLER WITH SAID PLATEN UPON PASSAGE OF THE END OF SAID PAPER SHEET BEYOND SAID RESPECTIVE FEED ROLLER, AND (D) MEANS IN THE REAR FEED ROLLER LEAD ELECTRICALLY RESPONSIVE TO THE ENERGIZATION OF THE SIGNAL LIGHT IN THE FRONT FEED ROLLER LEAD FOR EXTINGUISHING THE SIGNAL LIGHT IN THE REAR FEED ROLLER LEAD WHEN THE ELECTRICAL CIRCUIT THROUGH BOTH SAID LEADS IS COMPLETED. 